Permanent molds of the type mentioned consist of individual plates which are assembled to form a mold. Cooling ducts, through which a cooling liquid flows, usually water, are provided in the mold plates for cooling.
It has already been described in DE 30 38 289 A1 that the inner walls of the mold are often galvanically treated in order to make the inner wall of the mold resistant to the start-up strands which move into the mold at the start of the continuous casting and later to the liquid or solidifying steel. First of all, hard chromium plating was proposed for the surface treatment, but the service lives of such molds were relatively low, and therefore a metal layer of nickel together with hard material particles suspended in a temperature-controlled solution of one or more nickel salts is proposed for deposition on the inner wall of the mold. Silicon carbide (SiC) is to be used, in particular, as the hard material particles. At that time, it was possible to surprisingly determine that nickel layers doped with SiC particles reduce wear. It was surprising that, during the casting of steel in particular, neither the liquid metal which moved into the mold chemically attacked the SiC particles nor the particles broke out mechanically during hardening of the steel.
Such an Ni coating doped with SiC particles on the inner walls of the mold was also used successfully for copper molds, which were worn so severely on the inner side by use that they were no longer usable for continuous casting. The coating on the inner wall makes it possible to restore a mold with the desired inner dimensions which ensure optimum continuous casting.